128 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 23 



Assigning generic rank to Nodipecten seems advisable to the present 

 author. North did so, as did Rehder (1938, in Dall, Bartsch & Rehder, 

 p. 85). Other authors have regarded the unit as either a subgenus of 

 Chlamys or Lyropecten, or a synonym of the latter. The type species of 

 Lyropecten^ Pallium estrellanum Conrad (1857b, p. 313), is quite 

 distinct from any of the forms Dall mentioned in connection with Nodi- 

 pecten and certainly not congeneric. 



Dall's unit was poorly defined, nodosity being practically the only 

 distinguishing feature. The additional diagnosis given above includes 

 additional criteria which indicate more comprehensively what his inten- 

 tions seem to have been in proposing the unit. 



In addition to the type species, the following are also referable to 

 Nodipecten: subnodosus and magnificus Sowerby (eastern Pacific); 

 langfordi Dall, Bartsch & Rehder (Hawaii) ; noduliferus Sowerby (east 

 Africa, Mauritius and Reunion); corallinoides d'Orbigny (Spanish 

 Morocco ; islands ofif west Africa, from the Azores to St. Helena, and 

 possibly also a portion of the mainland, although no records located). 



Key to the eastern Pacific species of Nodipecten 

 1. Right valve with 10-11 ribs, left with 9-10 



subnodosus (Sowerby) 



(Western Lower California, Mexico; Scammon Lagoon to Cape 



San Lucas; Gulf of California to Negritos, Peru) 

 1. Right valve with 12-14 ribs, left with 13-15 



magnificus (Sowerby) 



(Galapagos Islands) 



Nodipecten subnodosus (Sowerby) 1835 

 Plate 43 



Pecten subnodosus Sowerby, 1835, p. 109. "Variat a, colore rufo-fus- 

 cescente, striis albis. Hab. ad Sinum Californiae [Gulf of Cali- 

 fornia]. /?, coloribus subvariegatis picta seu fusca, maculis albis 

 utplurimum notata. Hab. ad Insulam Platae, Columbiae Occi- 

 dentals [La Plata Island, Ecuador]. Y, testa depressiore, colore 

 aurantiaco nitente. Hab. ad Sinum Tehuantepec, Mexicanorum 

 [Gulf of Tehuantepec, west Mexico]. Found in sandy mud and 

 coral sand in from ten to seventeen fathoms." — Sowerby, 1842, p. 

 65, pi. 15, figs. 97, 112. "Var. 1. Brownish red with white striae, 

 from California. Var. 2. Variegated with brown and white patches, 

 from Isl. Plata, East Columbia [lapsus calami; West "Columbia"]. 

 Var. 3. A more depressed shell, of a bright orange colour, from Te- 

 huantepec Bay, Mexico." 



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